DESCRIPTION Cocaine dependence is a major public health problem affecting about 2 million Americans. In previous work, we have shown that approximately one-quarter of the population entering chemical dependency treatment has the adult form of attention deficit hyperactivity disorder (ADHD). Pilot studies have also shown that patients with the dual diagnosis of cocaine dependence and ADHD can be safely treated with stimulant medications (such as pemoline or methylphenidate) which reduced the symptom complex of ADHD and as well reduced the patients reports of craving for cocaine. The success in these open (unblinded) studies strongly suggests the importance of conducting a controlled clinical trial of psychomotor stimulant medications in a population of cocaine dependent and have childhood histories of ADHD will be recruited through advertisements in newspapers, radio, television, and by word of mouth. They will be screened for ADHD with a brief self-report screening instrument which has been validated in a prior study of patients with the ADHD/chemical dependence dual diagnosis. Volunteers who endorse a significant number of items on the screening questionnaire will be offered an in depth psychological evaluation for ADHD. The authors have developed and have had extensive clinical experience with a structured clinical interview to determine the presence of ADHD in adults with chemical dependency. Volunteers will also be assessed with the Structured Clinical Interview for DSM-IV and the Addiction cocaine dependence based on the clinical interview will be offered enrollment into a 12 week, double-blind, randomized, placebo-controlled trial with three treatment arms: placebo, pemoline (titrated up to 2 mg/kg/day), and methylphenidate (titrated up to 1 mg/kg/day). All volunteers will participate in an outpatient substance abuse group counseling program three times a week throughout the course of the study and a weekly individual one hour session of cognitive-behavioral psychotherapy. The major outcome variables will be cocaine use (by urine testing and self-report), other drug use (by urine testing and self-report), retention in the treatment program, assessment of symptoms for ADHD, and standardized reports of craving for cocaine. Additional analysis will be performed to determine whether the effects of treatment on cocaine use are associated with changes in ADHD symptoms. The identification of pharmacologic agents to treat a significant proportion of cocaine dependent individuals would be of great value.